The isolation of biologically important peptides from the thymus gland has been studied extensively in the last few years. Several peptides have been shown to play certain roles in T-cell maturation. Thymosin .alpha..sub.1, a highly acidic acetyl octacosapeptide isolated from calf thymus gland and characterized by sequence analysis has been reported to exhibit biological activities involved in the development of thymus-dependent lymphocytes (T-cells).
The isolation and characterization of thymosin .alpha..sub.1 was disclosed in U.S. Pat. No. 4,079,127. Synthesis of this peptide by solution and solid phase procedures was disclosed in U.S. Pat. No. 4,148,788.
An alternate solution phase synthesis for thymosin .alpha..sub.1 employing a different synthetic strategy was described by Birr and Stollenwerk, Angew. Chem. Int. Ed. Engl. 18, 394 (1979).